Master cylinder cast#/date code question

I'm looking at a master cylinder and my NCRS guide doesn't address date coding. Here's the information I have so far
The master cylinder has the numbers 5460346 on one side. On the other side it says 78 and below that it says D1.
Do I need the numbers from the front of the master cylinder or is this enough?
P.S. If anyone has a master cylinder dated July to early Novermber 1980 let me know
STW!
Platato



